The present invention relates to stator coil assemblies for low wattage motors and particularly to motors employed for timing devices as, for example, electrical programmer timers. Typically motors employed for this type of service application are synchronous motors employing a permanently magnetized rotor and a single continuously wound stator coil disposed annularly about the rotor.
Typically, low wattage synchronous timing motors are designed to operate at line voltage for example 120 volts RMS AC encountered in residential power service. Thus, programmer timers and other devices employing such small synchronous timing motors are intended to be connected to the power inlet of the programmer timer or device to be controlled with the timing motor. Typical of such applications are programmer timers for household appliances such as washing machines, dishwashers, clothes dryers; and, clocks employed on cooking appliances for controlling the duty cycle of the heating elements in the cooking appliance.
Typically, synchronous timing motors for these residential applications are wired into the appliance wiring harness concealed behind a control panel or cover and a service cord or power connection cable is provided for plugging into the residential power receptacle. Electromechanical programmer timers for such residential appliances have found widespread use because of their reliability, robustness and low manufacturing cost. Recently, it has been desired to interrupt the power to the timing motor for adding additional control features to the appliance yet retain the economical electromechanical programmer timer, thus, it has been required to provide a switching mechanism capable of handling the household power line voltage.
Recently it has become desired to provide electronic microprocessor based controls for certain appliances employing electromechanical programmer timers where household power line voltage is not practical and where a low voltage supply must be employed for safety considerations. Such a situation arises where it is desired to provide programmer timer control of a hot water heater where there is an increased hazard of electrical shock. It has thus been desired to use an existing electromechanical programmer timer for low voltage operation without redesign and the attendant increase in manufacturing costs associated with any such redesign, including retooling costs. Where it has been desired to utilize electronic control for low voltage applications, it has been desired to find a cost effective way to provide interconnection between an electronic circuit board having a microprocessor and an existing synchronous timing motor used in an electromechanical programmer timer.